1. Field of the Invention
The present invention relates to a miniature blower fan mounted in a miniature electronic system for dissipating heat for microchips in the electronic system.
2. Description of Related Art
FIG. 1 illustrates a conventional blower fan comprising an impeller 10 having an inner circumferential wall to which a magnet 11 is fixed. An axial seat 12 protrudes from a center of the impeller 10, and a shaft 13 is fixed to the axial seat 12. A web 14 extends radially outward from an outer circumferential wall of the impeller 10. A plurality of radially extending vanes 15 are formed on the web 14 and spaced at regular intervals. When the impeller 10 turns, the air currents on top of the impeller 10 are driven by the vanes 15 and output sideward for dissipating heat for an electronic system.
Due to developments in precision and complication of layouts of integrated circuits, complicated circuit designs cause rapid temperature rise of the microchips, especially for those in miniature electronic systems. Conventional solutions including increasing the heat-dissipating area by fins and using heat-conductive tubes to transfer heat energy fail in current systems in which the heat energy accumulates rapidly. Further, difficulties exist in miniaturization of the conventional blower structure such that the conventional blower structure could not be used in miniature electronic systems.
If the thickness of the above conventional blower fan is directly reduced for miniaturization purposes, the heat-dissipating capacity of the blower fan is adversely affected directly. This is because the space for installation of the stator is limited and large-power stator coils could not be used once the overall thickness of the impeller 10 is reduced. Further, reduction in the overall thickness of the blower fan also limits the area of the impeller 15. The speed of the air currents and the wind pressure are reduced.
Hence, to meet the requirements of the developments in precision and complication of layouts of integrated circuits, a novel miniature blower fan is required for solving the heat-accumulation problem, for assisting in rapid heat-dissipation for the microchips, and for maintaining normal operations of the whole system.